docs: def normalize(self, text):
          """Normalize unicode, hyphens, whitespace, and some chemistry terms and formatting."""
          text = super(ChemNormalizer, self).normalize(text)
          # Normalize element spelling
          if self.chem_spell:
              text = re.sub(r'sulph', r'sulf', text, flags=re.I)
              text = re.sub(r'aluminum', r'aluminium', text, flags=re.I)
              text = re.sub(r'cesium', r'caesium', text, flags=re.I)
          return text